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CVE-2021-31886

A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethern...

No known exploitation. EPSS puts it in the 88th percentile. A vendor fix is available.

CVSS 3.19.8CriticalEPSS percentile88th3.1% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD, BDU, CSAF

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

  • Siemens Nucleus ReadyStart V3Affected: All versions < V2017.02.4Upgrade to: not statedStated by: CVE record
  • Siemens APOGEE MBCAffected: All versionsUpgrade to: not statedStated by: CVE record
  • Siemens APOGEE MBCAffected: All versionsUpgrade to: not statedStated by: CVE record
  • Siemens APOGEE MECAffected: All versionsUpgrade to: not statedStated by: CVE record
  • Siemens APOGEE MECAffected: All versionsUpgrade to: not statedStated by: CVE record

Versions as the sources state them. 38 more products have version data. Full version matrix after sign-in

Is your organisation exposed?Request an assessment to establish which checks fit your systems.

Coverage timeline

2 publishers

  1. Researchers used Anthropic's Claude AI to successfully port a pre-authentication RCE exploit to a different WAGO PLC model, demonstrating the feasibility of AI-assisted OT vulnerability exploitation.

    ·The Hacker News summary

Sourced from public security reporting — each date is when it was published, not when it happened.

What it is

From the CVE record

The TCP/IP stack and related services (FTP, TFTP) of the networking component (Nucleus NET) in Nucleus Real-Time Operating System (RTOS) contain several vulnerabilities, also known as "NUCLEUS:13" and as documented below. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends countermeasures for products where updates are not available.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS88th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

3.1% chance of exploitation activity in the next 30 days, which ranks it in the 88th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

5 events over 1108 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. Publishedweakness classified, att&ck mapped

Affected products

And 54 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 25 more references. See all after sign-in

In the news

Watch the software you run.

My Stack ranks new CVEs for your products by real-world exploitation, so the next serious one reaches you without reading every advisory.

We'll flag the next CVE, public exploit or patch for Nucleus NET, not every advisory.